They look like star polyps (pachyclavularia) and palythoa/zoanthus to me.
That looks to be aiptasia. Heres some good ways to get rid of it. NanoReefing.Com - Your ultimate guide to saltwater aquariums
Yeah right now its not. But sure enough when they start to populate the tank they will grab everything in their path. Its a good thing you noticed the, now and not later. Definitely go with the pep shrimp. They are cool. And you might get lucky and they will possibly take care of the aptasia problem for you. Hope you get a bunch of pep shrimp that do like aptasia!! Good luck!
I agree, if you put it off in hopes that you can get a natural "solution", you'll end up with a bunch of reproducing aiptasia and a lot of new tank mates that decide they dont much care for the taste.My experience with peppermint shrimp has been that they'll take care of the smaller ones (perhaps), but ignore the bigger ones. I'd deal with that one chemically before it gets a chance to reproduce.